Campaign

Marcus, It's Your Father - 5 gamerpoints - Story Progression in Prologue (Standard or Arcade).
Swimmin' in Glowie Gravy - 10 gamerpoints - Story Progression in Act 1 Chapter 2 (Standard or Arcade).
We Struck Gold, Son! - 10 gamerpoints - Story Progression in Act 1 Chapter 3 (Standard or Arcade).
My Turf! Cougars Territory! - 10 gamerpoints - Story Progression in Act 1 Chapter 5 (Standard or Arcade).
Putting it Scientifically… - 10 gamerpoints - Story Progression in Act 1 Chapter 6 (Standard or Arcade).
Okay, Now We Find Hoffman - 10 gamerpoints - Story Progression in Act 2 Chapter 1 (Standard or Arcade).
Oh Yeah, It's Pirate Time - 10 gamerpoints - Story Progression in Act 2 Chapter 5 (Standard or Arcade).
Thanks for Flying Gas Bag Airways - 10 gamerpoints - Story Progression in Act 2 Chapter 7 (Standard or Arcade).
Anvil Gate's Last Resort - 10 gamerpoints - Story Progression in Act 3 Chapter 1 (Standard or Arcade).
Was it Good For You? - 10 gamerpoints - Story Progression in Act 3 Chapter 2 (Standard or Arcade).
Lost Your Good Driver Discount - 10 gamerpoints - Story Progression in Act 3 Chapter 3 (Standard or Arcade).
Brothers to the End - 10 gamerpoints - Story Progression in Act 3 Chapter 5 (Standard or Arcade).
Think You Can Handle That? - 10 gamerpoints - Story Progression in Act 4 Chapter 3 (Standard or Arcade).
Baird's Favorite Kind of Toy - 10 gamerpoints - Story Progression in Act 4 Chapter 5 (Standard or Arcade).
Welcome To - 10 gamerpoints - Story Progression in Act 4 Chapter 6 (Standard or Arcade).
Look at That, Instant Summer. - 10 gamerpoints - Story Progression in Act 5 Chapter 2 (Standard or Arcade).
Ok. Faith. Yeah. Got It. - 10 gamerpoints - Story Progression in Act 5 Chapter 5 (Standard or Arcade).
We've Finally Got a Tomorrow - 10 gamerpoints - Story Progression in Act 5 Chapter 6 (Standard or Arcade).

Game Completion

Ready for More - 50 gamerpoints - Complete all campaign Acts on Casual or Normal Difficulty (Standard or Arcade).
Ain't My First Rodeo - 50 gamerpoints - Complete all campaign Acts on Hardcore Difficulty (Standard or Arcade).
That's Just Crazy (unlocks in-game content) - 75 gamerpoints - Complete all campaign Acts on Insane Difficulty (Standard or Arcade).

Collectibles

Collector - 5 gamerpoints - Recover 5 Campaign Collectibles (any difficulty, Standard or Arcade).
Pack Rat - 10 gamerpoints - Recover 20 Campaign Collectibles (any difficulty, Standard or Arcade).
Hoarder - 15 gamerpoints - Recover all 42 Campaign Collectibles (any difficulty, Standard or Arcade).
Remember the Fallen - 15 gamerpoints - Recover all 15 COG Tags during the Campaign (any difficulty, Standard or Arcade).

Co-Op

My Fellow Gears - 50 gamerpoints - Complete all Campaign Acts in Co-op (any difficulty, Standard or Arcade).
We Few, We Happy Few... (unlocks avatar award) - 50 gamerpoints - Complete all Campaign Acts in 4 player Co-op (any difficulty, Standard or Arcade).

Skill-based

Level 5 - 5 gamerpoints - Reach level 5.
Level 10 - 10 gamerpoints - Reach level 10.
Level 15 - 15 gamerpoints - Reach level 15
Level 25 - 25 gamerpoints - Reach level 25.
Level 50 - 50 gamerpoints - Reach level 50.
Judge, Jury and Executioner - 10 gamerpoints - Get a kill with every possible execution finishing move (any mode).
Wreaking Locust Vengeance - 10 gamerpoints - Get a kill with every Locust monster in Beast mode (any difficulty).
Enriched and Fortified - 10 gamerpoints - Complete all 50 waves of Horde mode (any difficulty, any map).
It's All About the Loot! - 25 gamerpoints - Earn the Bronze "Loot Courtesan" medal.
All for One, One for All - 10 gamerpoints - Earn the Bronze "Force Multiplier" medal.
First Among Equals - 25 gamerpoints - Earn the Silver "Number 1" medal.
Award Winning Tactics - 25 gamerpoints - Earn at least one Onyx medal.
Seriously 3.0 (unlocks in-game content) - 100 gamerpoints - Reach level 100 and earn every Onyx medal.

Accessibility

Welcome to Versus - 10 gamerpoints - Kill 10 enemies in Team Death Match (Standard or Casual).
The Versus Sampler Platter - 10 gamerpoints - Complete one match of all six Versus game modes (Standard or Casual).
Welcome to Horde Mode - 10 gamerpoints - Survive the first 10 waves of Horde mode (any difficulty, any map).
Welcome to Beast Mode - 10 gamerpoints - Survive all 12 waves of Beast mode (any difficulty, any map).
Welcome to Arcade Mode - 10 gamerpoints - Complete 5 Arcade Campaign chapters in co-op (any difficulty).

Multiplayer Only

Welcome to the Big Leagues - 0 gamerpoints - Demonstrate your skill in Casual Versus multiplayer.
Wait, What Time is it? - 10 gamerpoints - Earn the maximum Consecutive Match Bonus in Versus multiplayer (Standard or Casual).
Socialite - 70 gamerpoints - Earn the Onyx "War Supporter" medal.